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What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

New
D'Aarsonval movement meters of increased sensitivity which do not need zero
setting adjustments.

A new
computer designed filter to reduce noise from stations broadcasting subcarrier
auxiliary music services. No other tuner uses such a filter.

Exclusive
McIntosh PANLOC is used for installation.The PANLOC system gives you absolute
ease of installation, operation and maintenance.

PANLOC is
the first professional installation technique to be used on stereo
instruments. In the PANLOC system a
metal shelf is mounted first. The tuner slides into position on this shelf.
Depressing the front panel PANLOC buttons, locks the tuner firmly into position
against the mouting panel.

Onec you
have enjoyed the outstanding performance of the Mr 73, you will understand why
McIntosh products have earned their reputation as "the best". Your
McIntosh MR 73 tuner will give you years of the finest possible reception, and
will be a valued part of your home music system.

FM SECTION

This is
divided into two separate modular sections:

1 - The 100
mHz Radio Frequency (RF) Section

2 - The
FM-IF and Detector Section

The first
section houses the complete FM-RF front-end part of the AM_RF circuits. A
special four section, variable tuning capacitor provides a high degree of RF
selectivity and excellent spurious response rejection. The problem of image
rejection has been greatly reduced in the Rf section of the MR 73.

The two
stage parallel-fed-cascode junction
field effect transistor (JFET) RF amplifier gives better sensitivity and higher
gain than conventional one-stage
amplifiers. The use of JFET's helps to further reduce the problem of front end
overload in strong signal areas.

A mixer
using a JFET has been designed for high sensitivity and freedom from overload.
Low temperature coefficient components have been designed into the FM local
oscillator to revent frequency drift. The frequency stability inherent in the
local oscillator makes automatic
frequency control (AFC) unnecessary. The rate of drift of the local
oscillator is less than ten parts per million per degree cantigrade.

Both the FM
and AM-RF front ends have been designed in the same completely encased metal
modules. This design gives protection against radiation or interference. The RF
circuits of the MR 73 exceed the FCC requirements for suppression of oscillator
radiation.

The MR
73 has antenna connections for either
300 Ω twin lead transmission line or
75 Ω coaxial cable. The normal input
impedance of the first RF amplifier is 75 ohms. Impedance match to 300 Ω is provided by a McIntosh designed balun
transformer which has negligible losses. Connections for a 300 Ω line are made with new push type terminals. No
tools are required. A type F male linear phase characteristics of the IF
amplifier.

The FM-IF
and Detectorsection design required
extended engineering time and testing and uses the latest concepts in
integrated circuits and crystal filters. The FM-IF consist of two integrated
circuits and two phase linear crystal filters. They combine to give a total
gain of over 120 dB (the signal is amplified to over 1,000,000 times its
original level). The response curve has a nearly flat top with linear phase
characteristics. The skirts of the response curve are very steep. The maximum
width is 240 kHz at -3 dB and 400 kHz at -60 dB. The response curve is
symmetrical each side of the center frequency. The crystal filters are
permanently sealed and do not require adjusting. The IF cannot drift nor
vibrate out of adjustment.

Each of the
two integrated circuits used in the FM-IF of the MR 73 contain 16 transistors,
3 zenar diodes, 5 diodes and 23 resistors, all on a single monolithic silicon
chip.

The
exceptionally high gain of the two integrated circuits assumes "hard
limiting" at very low levels of input signals.

A
"phase" or "Foster Seeley" discriminator has been designed
to complement the integrated circuit IF section. The IF section has exceptionally high gain and hard limiting
characteristics, yet the capture ratio is quite low. The detected output signal
of the discriminator is extremely low in distortion content.

De-emphasis
of the discriminator output restores the frequency amplitude characteristics o
the same level they were before transmission.

C.FM Stereo
Multiplex Section

McIntosh
laboratory has developed a special detecting circuit in the multiplex section.

A particular advantage of this circuit in the
elimination of the critical adjustments necessary with commonly used matrixing
circuits. The circuit detects the L-R sidebands, then automatically matrixes
the recovered information with the L+R main carrier signal. This yields the
left and right program output with maximum separation.

The 19 kHz
pilot signal is filtered from the composite stereo input signal, amplified by a
special limiting amplifier, doubled to the 38 kHz carrier sognal. The new combination of signals is fed to the
special detector circuit mentioned above. Balanced full wave detectors are used
to cancel the 38 kHz conponents in the output.

The SCA
(Subsidiary Communication Authorization) signal must be removed from the
composite output. This is accomplished by the use of a new "Image
Parameter" band elimination filter that has been computer designed. The SCA filter
rejects SCA signals without impairing stereo performance.

FM muting in
the McIntosh MR 73 operates by detecting ultra-sonic noise which is present
when tuning between stations or when receiving a weak station. The muting
circuit can be activated or defeated by the use of the muting switch on the
front panel. The level of muting desired can be adjusted by the muting level
control on the top panel. Varying the muting control adjusts the threshold at
which the muting takes effect.

When the 19
kHz carrier of a stereo signal is received, the automatic FM stsreo switching
circuit activates the multiplex decoding circuit. This lights the stereo
indicator. The circuit switching is all done electronically with no clicks. The
automatic stereo switching can be defeated by turning the mode selector switch
to FM Mono (In this position the stereo indicator will still light to indicate
the presence of a stereo signal). On monophonic
transmissions the stereo switching is inactive at all times, assuring a
greater signal to noise ratio. The stereo switching circuit has been designed
so that noise will not activate it.

AM SECTION

The
"State-of-the-art." in electronic technology has been incorporated by
McIntosh into the MR 73 with the use of metal oxide silicon field effect
transistors (MOSFET's) in the AM section.
An AM-RF amplifier circuit includes a three section variable tuning
capacitor in the metal enclosed shielded module, which also houses the FM-RF
front end. The Am-RF amplifier uses a
dual-insulated gate MOSFET to obtain more overload protection against strong
local stations than can be obtained with conventional bipolar transistors.

The AM-RF
mixer is also a dual-insulated gate MOSFET. The use of MOSFET's in the RF
amplifier and mixer provides the MR 73 with very little cross modulation
(spurious response) and the image rejection is very good.

Three double
tuned IF transformers are used to obtain a high degree of selectivity yet still
allow good Amfidelity. A 10 kHz whistle filter has been incorporated at the
output of the AM detector. Its purpose is to supress hetrodyning that occurs
between adjacent AM carriers.

To increase
the "pulling power" of the AM section of the MR 73, connect an
external antenna at the rear apron of the unit by using a push connector. An
internal transformer matches the external antenna to the input impedance of the
AM front end. An optional highly sensitive loop stick antenna is also provided
for local or strong stations. A switch on the back panel selects either
loopstick or external antenna.

An AM
sensitivity switch has been provided to decrease both the gain of the RF
amplifier and the noise between stations.

Audio
Preamplifier Section

An audio
amplifier has been incorporated in the McIntosh MR 73. It in creases the audio
level from the AM or FM multiplex outputs to a level sufficient to drive a
preamplifier or other accessory equipment. The audio amplifier consists of 2
separate amplifiers, each amplifier having three transistors. The design uses
considerable negative feedback. Negative feedback helps to achieve low
distortion, wide frequency response, and unexcelled stability. Each audio
amplifier has two low impedance outputs. One is a fixed output set at 2,5
volts. The second output is variable by the volume the control on the front
panel.

By
cross-coupling a small portion of one channel into the other in the audio
amplifier, the residual alternate channel information can be cancelled, thereby
further increasing the stero channel separation.

Also
included in the audio section is a Stereo Filter switch. With the Stereo Filter
turned on and waek stations are being received, stereo noise is reduced, but
still allows ample stereo listening performance.

Power Supply

Special
design attention has been given to the power supply section of the McIntosh MR
73. Two separate rectifier circuits are used in the MR 73.

The 16 volt
regulator is the power heart of teh Mr 73. All signal stages throughout the
unit are powered from this regulator. The 16 volt regulator is very elaborate
in design, using a specially selected transistor and associated circuit. The
regulator uses electronic filtering to insure the lowest possible background
hum level, maximum stability and extremely good regulation.

A half wave
rectifier and filter, supply the DC high voltage needed for the anode of the
multipath indicator. The second power supply is a full wave rectifier which
supplies DC to the multiplex indicator and to the voltage regulator.

Specifications

FM Section

Frequency:
88 to 108 MHz

Useable
Sensitivity: 2,5 microvolts at 100%
modulation (±75 kHz deviation) for less than 3% total noise and harmonic
distortion in accordance with IHF standards

His power is
sufficient to dominate the bustle of the noisiest nights.

The sound quality is
perfect at both ends of the audible spectrum. The filter "High"
eliminates surface noise disks, tapes breath.

The "Low"
filter removes background noise interference.

You can easily
select one of six listening sources.

Other benefits.

Sockets for two tape
recorders and sockets for stereo
microphone on the front panel.

The
particularly nice thing about the Marantz 1060 is that it will go with just
about any sized speaker system and still put out enough power to cover a room
full of people. 60 Watts of power. And more like 90 Watts under typical
listening conditions. At full volume or low level the distortion stays about
the same. Or perhaps we should say "lack of Distortion". The Model
1060 has less than 0,5% total harmonic and intermodulation distortion.
Typically 0,1%. Perhaps that's why it's received rave reviews in audio
publications throughout the world. And perhaps that's why so many have been
sold. It's features, also, place it among the very finest. There's a high
filter to eliminate record scratch and tape hiss. And a low filter to cut hum
and rumble. Other features include inputs for two tape recorders, as well as
front panel stereo microphone input jacks. The list goes on. But for the 1060
listening is believing. You can do both.

The TD 318
is the logical conclusion of the realisation of the experience that Thorens
have made with the development of the world acknowledged "Reference"
and "Prestige" turntables, combined with more than 100 years of
tradition in the reproduction of music. The Thorens TD 318 - a concept with
future.

The
Thorens-motor drives the turntable platter by means of a rubber belt. The
natural elasticity of the belt prevents most motor vibrations from reaching the
plater and, therefore, the pick-up stylus. In more than 20 years of continuous
development, Thorens has reduced the very few disadvantages of belt drive to an
absolute minimum and has brought it to a level of technical perfection which is
not approached by any other system known today. A particular development is the
Thorens acceleration clutch, which prevents the belt from stretching, thus
reducing the starting time and eliminating chassis vibration.

Because of
the high performance required by desceming listeners, Thorens has decided to
retain its own unique belt drive system as long no better drive system is
developed in Thorens laboratories or elsewhere.

The Thorens
Floating Suspension

Every
turntable must be damped by a suspension system to prevent the sensitive
pick-up from enviromental vibration and from acoustic feedback. If the springs
are placed between motor and turntable platter, they than fulfill the
additional requirement of decoupling motor vibrations almost completely from
the turntable and the pick-up system.

Chassis 1
carries the motor and controls. Chassis 2 which is isolated by three easily
adjustable leaf springs carries the platter and tone arm. The chassis of the
318 is made of amedite material which absorbs resonances resulting in cleaner
and more precise sound.

Specifications
mean very little to how good a turntable sounds. The selection of the
appropriate materials, the individual tuning, and the harmonisation of all the
components are decisive in determining the sound quality.

Thorens have
been involved in the production of turntables since the existance of records.

For optimum
in tracking ability it is not sufficient that a tone arm has a low bearing
friction. It is much more important that it has a low effective mass, because
high mass prevents the stylus from following the imperfections (warp or ripple)
of the record as it should do.

To overcome
hgh effective mass one can increase the stylus force, but this results in
excessive record wear.

In addition,
the TP 21 is a straight arm and not S-shaped. The necessary offset angle is
independent of the arm shape. A special surface treatment of the tone arm tube
absorbs all undesirable resonances of the tone arm.

In the trend towards
higher output powers, the CA-610 is unique. The minimum 40 Watts per channel is
generous. With most home listening done between 1 and 10 Watts it can even be
overwhelming. But the tremendous sense of scale, of unstrained ease in reproduction,
and vast reserves of power, is more than you would expect from 40 Watts (and
certainly more than you would get from most competitive amplifiers in the same
class).

Capable of
recapturing for you the thrill of an orchestral ‘tutt’ or a live rock concert
the sound is never choked in noise or smeared with distortion at low levels.

From a mere 250 mW
up to the full rated output of 40 Watts, and for all frequencies from 20 Hz to
20 kHz, the CA-610 gives no more than 0,05% THD. At 20 Watts output that drops
to 0,01% (0,005% at 1 kHz) And signal-to-noise ratio is 75 dB for a 2.5 mV phono
input. It all adds up to a new experience in impressive, powerful reproduction.
The meters cover outputs from 0,01W to 100 W in one unswitched range a valuable
feature that lets you know how much power your speakers are handling.

Ultra Low Distortion
Tone Control Circuitry.

The CA-610 tone
controls offer the ideal combination of characteristics; simple to operate,
they add virtually no distortion to the final sound. You can boost or cut
treble and bass to suit your mood, your choice of music, or the acoustics of
your room and speakers. And you can do it all without sacrificing quality for
the convenience.

The special Yamaha
negative feedback circuitry, and perfect crystal device trchnology used in the
semiconductors, give smooth and precise control, with perfectly flat ‘0’ (zero)
position. And so that you can compare the effects of your tone control settings,
there are separate ‘defeat’ switches for bass and trebl, instantly bypassing
the boost and cut circuits. Thespecial Yamaha design ensures that distortion is
held to a minimum, typically contributing only 0,008% from 20 Hz to 20 kHz with
90 dB S/N ratio and 0,4 mV residual noise for the Aux terminals.

Music waveforms are
incredibly complex, and the pulse plus sine wave response of the CA-610 shows
how faithful reproduction of such signals is.

Clearly Audible Advance in Quality

The CA-610 is more
than the sum of its parts. More than a combination of superb equalizer
amplifier for record reproduction, sophisticated tone controls, and a powerful
main amplifier. It’s truly integrated. And not only is power high, the
distortion hits new lows at all listening levels form the quietest to the very
loudest.

A Fantastic Range of
Operating

The Ca-610 combines
full tape monitoring and dubbing facilities with a new ability. Now, not only
can you copy direct from one tape deck to another in any direction, and monitor
recordings while they are being made (if you have a three-head tape deck),
You can also listen to any program source while you are recording. This lets
you save time by dubbing at double speed, while relaxing to the sound of your
favorite record. Or your can record an FM program for later audition while
listening to a pre-recorded tape.

More Than an
Amplifier - A Complete Control Center

If you hear the
Ca-610 you can hardly fail to want it. If you select it, you are sure to want
the matching tuner; the CT-610. Together, they stand right at the top of their
class, and from the nucleus of a first quality home stereo system.

The CA-610 has
a precision volume control, perfectly in balance within +_1 dB form 0 to
-70 dB, with an attenuation curve that makes it easy to set the exact level you
want. Then there is the -20 dB muting switch for an instant cut in volume. And
the useful Rec Out Off position, cutting out the effect of tape decks when not
recording. A host of useful features.

Advanced Equalizer
Design

With its four-stage
direct-coupled configuration, the equalizer resembles power amplifier design
more than it does conventional circuitry. All four stages (differential
current-mirror first stage plus emitter/ collector/ emitter-follower) operate
under constant current bias, and give excellent open loop performance. The
result is high stability and ultra-low distortion with moderate NFB for superb
dynamic characteristics.

The Arcam
Delta 70 compact disc player has been designed to provide the best possible
sound quality from compact disc digital audio. Together with the Arcam Delta
90, Delta 80 and the range of Arcam loudspeakers, the Delta 70 makes up the
first complete CD based hi-fi system to be both designed and manufactured in
great britain.

Design
Philosophy

Most
specialist hi-fi companies merely "badge engineer" or modify mass
produced Cd players, and are restricted to using their normal plastic chassis
and standard circuit boards. From the outset, A&R Cambridge limited
realised that this approach was simply not good enough to produce a Cd player
to the standard demanded of an Arcam product. A&R therefore went to the
trouble and expense of procuring full CD manufacturing licence. This gave our
designers the opportunity to engineer the Delta 70 to a superior mechanical and
electronic standard, incorporating much of the experience gained in producing
some of the world's most acclaimed hi-fi amplifiers. Consequently, not only
does the Delta 70 sound better, it is also visually more appealing and much
easier to use than other CD players on the market.

Versatility

Careful
ergonomic design has simplified the operation of the Delta 70 to the extend
that anyone can play a compact disc on it within a few seconds of first
encountering the player. This is in marked contrast to many otherwise admirable
CD players, whose complex control layout and over-elaborate displays frequently
give rise to continued 'technofear', even amongst the most experienced users,
let alone normal music lovers.

The controls
on the front panel of the Delta 70 are divided into two groups. On the upper
level they comprise just those needed to load, play and stop a compact disc.
One the lower level we have included the pause button (conveniently located
directly underneath the main stop button) and all the commonly needed
programming functions. These include 3 speed search facilities and the previous
and next track selection buttons, which will also access index points within a
track. An easy to program memory is provided; this is capable of memorising the
order of play of up to 20 different tracks.

To make
operations even easier and more convenient the Delta 70 can be remote
controlled using our optional infra-red remote control handset.

The displays
on the Delta 70 have also been kept deliberately simple. An attractive and easy
to read 4 digit fluorescent display provides readout of track and index
numbers. It can also be used to indicate the total playing time of the disc and
the elapsed time of each track as it is played.

Typical of
the care and attention that our designers have taken is the location of the
status indicator LEDs, which are provided for the power pause, and time/track
functions. These are located just where they are needed, above the appropriate
buttons, rather than buried elsewhere on the fascia.

Flexibility

The Delta
70's audio outputs are comprehensive, with both direct and variable outputs
being provided. The latter is controlled via a low impedance ALPS potentiometer
and is designed to feed a high quality power amplifier directly without the
loss of quality associated with a conventional preamplifier. A headphones
socket with adjustable output level is also included. This is driven from its
own high quality amplifier, which has sufficient gain and power to drive almost
any pair of moving coil headphones. Finally a digital output socket is fitted,
for use with outboard D/A systems and for futur applictaions such as CD-ROM and
CD-I.

ElectronicDesign

To recover
as much information from the disc as possible the Delta 70 uses a swing arm
single-beam laser pickup. This produces an inherently accurate signal from the
disc than the 3-beam system used in most players. The disc playing mechanism is
mounted on a fully floating sub-chassis to isolate it from external vibration.
Allied to this is a 64K DRAM-based adaptive error correction system, which is
one of the most comprehensive ever employed in a domestic Cd player. Taken
together these features ensure the greatest possible integrity of recovered
digital signal.

The digital
signal is then processed using twin linear phase 120 element finite impulse
response digital filters. These ultra stable low noise filters keep the audio
band remerkably flat but dramatically attenuate the unwanted h.f. components of
the audio signal. They are followed by dual 16 bit prcision DACs, operating in
the classic four times oversampling mode at a frequency of 176,4 kHz. To
enhance their timing linearity (and
hence sound quality) the Dacs are fed from a unique. A&R designed precision
master oscillator.

Great care
has been taken with all aspects of teh DAC and post-DAC filter and output
circuitry to preserve this hard-won sound quality. Audiophile quality
components been used throughout these stages, which have been assigned no less
than five fully stabilised, critically decoupled power supplies. Integral withh
the output filter which removes unwanted digital 'hash'. The circuitry is of an
all-discrete transistor, direct coupled, class A design, which totally
eliminates sound degrading interstage coupling capacitors from the signal path.

Model
ST-540's direct drive and fully automatic operation provide perfection and
highest quality. Quartz-lock insures
that the turntable rotation will not vary under changing load or
voltage. Rotation precision is maintained at ±0,0001% and rumble has been
almost eliminated. Wow and flutter have been reduced to negligible levels by
improvements in the direct drive.

The Low
mass, straight tonearm, is statically balanced for improved tracability, has a
removable headshell and antiskating device. The optional moving magnet (MM)
cartridge with diamond stylus assures faithful reproduction for the utmost in
listening pleasure.

Acoustic
feedback reduced.

Improvements
made in the subchassis have greatly reduced acoustic feedback. The independent
suspension of the floating chassis improves howling performance and pushing the
operation buttons does not move the chassis. The hefty, solid base stands
firmly in place when the operation buttons are pushed.

All-front
operation.

All
operations are by feather-touch buttons located on the panel. Even cueing can
be performed with the dust cover closed. Operational simplicity is combined
into this convenient arrangement.

Fully
Automatic operation

Simply place
your favorite record on the platter, close the dust cover and push the button.
That is all it takes for this fully automatic turntable. Lead-in is automatic
and the tonearm will return to rest and turn off power when the record ends.

Oil-damped
cueing.

The delicate
stylus needle is gently lowered into the record groove with oil-damped cueing.
Thus you are now assured of safer and easier record play with no impact shock
when the needle contacts the record.